https://doi.org/10.1140/epjd/e2012-20545-3
Regular Article
Electronic sputtering: angular distributions of (LiF)nLi+ clusters emitted in collisions of Kr (10.1 MeV/u) with LiF single crystals
1
Centre de Recherche sur les Ions, les Matériaux et la Photonique
CIMAP-GANIL (CEA-CNRS-ENSICAEN-UCBN), BP 5133, Boulevard Henri Becquerel, 14070
Caen Cedex 05,
France
2
Physics Department, Universidade Federal de Santa
Catarina, Campus
Trindade, 88040-970
Florianópolis,
Brazil
3
Physics Department, Pontifícia Universidade Católica do Rio de
Janeiro, Rua Marquês de São Vicente
225, Gávea, 22453-900
Rio de Janeiro,
Brazil
a e-mail: rothard@ganil.fr
Received:
21
September
2011
Received in final form:
13
January
2012
Published online:
27
March
2012
A combination of imaging techniques (XY) and time-of-flight (TOF) spectroscopy was used to measure the complete velocity vector of sputtered positive secondary ions in collisions of Kr33+ (10.1 MeV/u) with well prepared LiF single crystals in the electronic stopping regime. The angular distributions of (LiF)nLi+ clusters become broader with increasing cluster size n. This could be an indication of contributions from different ejection mechanisms. The experimental secondary ion angular distributions can be fitted by a simple cosine function of the type N(θ) = A cosm(θ), but it does not reproduce the shape of the jet-like structure observed for the emission of neutral LiF particles perpendicular to the ion beam. Therefore, the cluster emission hypothesis does not explain in a simple way the observed narrow jet.
Key words: Atomic and molecular collisions
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2012